Flare was another matter. Despite the use of the included lens shade and Tamron’s BBAR (Broad-Band Anti-Reflection) multi-coating, I did encounter certain situations where flare, more so than ghosting, crept into a shot, notably with very bright light sources backlighting a scene. But these instances were infrequent and rarely intrusive enough to spoil the shot. Still, I’d keep the shade on, as it likely helped prevent flare in other situations and certainly kept raindrops from hitting the lens when I got caught in a shower.

This lens also features full-time manual focus override. This feature came in handy when photographing animals behind wire at Chicago’s Lincoln Park Zoo. There is, of course, the option of manual focus via the lens’s own focusing switch or, in the case of my D300, the camera’s focus selector. Just be careful that these settings are not working at cross-purposes with each other. Either way, manual focusing was smooth—not quite what it was for the old manual focus lenses but on a par with most AF lenses. And while it won’t get you as close as Tamron’s macro-focusing 70-300mm, close focusing is good enough for a tight headshot. (Tamron—any chance of producing a hybrid of these two lenses in the next generation?)

Meerkat, Lincoln Park Zoo

I took advantage of the VC function in this indoor exhibit with limited lighting, setting the lens to 300mm (= 450mm), with shutter speeds ranging from 1⁄50 to 1⁄60 sec at f/5.6 (ISO 800). This meerkat had clearly been busy digging before posing for this shot.

Next comes the question of lens distortion. Barrel distortion at 70mm was faintly detectable; was neutralized when you first hit three-digit focal lengths; but soon began to bow inward at around 130mm. That said, even at 300mm, pincushion distortion was never serious enough to ruin a picture and is certainly easily corrected. What’s more, I found vignetting to be very mild even with the lens wide-open. In practical situations, I doubt you’d notice any vignetting, especially owing to the lack of darkened corners when shooting at maximum aperture. However, you may detect faint vignetting in even-toned subjects, such as blue sky, unless you stop down (less so at 300mm than at 70mm). I should add that with a maximum aperture of f/4 at 70mm, this lens is a drop faster than some of its variable-aperture counterparts that start at f/4.5.

Black Rhinoceros, Lincoln Park Zoo

I set the D300 to continuous AF, with the lens at the 300mm zoom setting, and kept shooting as the rhino moved toward me. As you can see, the lens picks up startlingly revealing details in the horn and face. I activated VC for this 1⁄160 sec exposure at f/6.3 (ISO 800).

In Conclusion
This lens blew me away. I found edge-to-edge sharpness very satisfying, especially for a lens easily under $500. And I loved this lens’s responsiveness when confronted with challenging subjects, like ducks and gulls whizzing past me. I quickly learned to appreciate the USD mechanism as I began paying attention to how beautifully and quietly the lens was working.

And as for image stabilization, I was amazed at some of the results. In at least one series of handheld exposures, VC helped prevent camera shake and maintain sharpness beyond five steps below the optimum shutter speed. Granted, this might be a stretch in windy conditions or where you’re surrounded by vibration-inducing traffic, but on a quiet street on a balmy day, it was doable—and with correct camera-handling techniques, I might add.

Still, to be on the safe side, I wouldn’t go more than the manufacturer’s recommended four steps with VC engaged, or even three steps for added assurance. (However, be sure to disengage this feature while shooting with a tripod-mounted camera when you exceed that four-step range, as VC may actually introduce vibration.) You can immediately tell when VC is engaged: the viewfinder image is much steadier than without VC, helping you better compose the shot.

All in all, I made over 3000 exposures with the Tamron SP AF70-300mm VC. And the impression I came away with is that this lens is definitely a keeper. When you factor in performance, overall design, and price, it all amounts to a very engaging lens that begs to be used again and again.

Architectural Detail: Glass Structures

Walking along the Chicago lakefront, I noticed these structures looming upward. I set the lens to 230mm (=345mm) and it captured detail and clean lines and a snappy image from edge to edge. Given the windy conditions, I opted to play it safe with a faster shutter speed of 1⁄320 sec (ISO 800), even though VC was active.

Technical Specifications
Tamron’s SP AF70-300mm F/4-5.6 Di VC USD
Lens Construction (Groups/Elements): 12/17
Diaphragm Blade Number: Nine (rounded diaphragm)
Minimum Aperture: F/32-45
Minimum Focus Distance: 1.5m (59.05”)
Macro Magnification Ratio: 1:4 (at f = 300mm: minimum focus distance: 1.5m)
Filter Diameter: 62
Weight: 26.98 oz (765g)
Length: 5.61” (142.7mm)
Full Length: 5.9” (151.1mm)
Diameter: 3.21” (81.5mm)
Accessory: Petal-shaped lens hood (included)
Mount (Full-Frame/APS-C): Nikon, Canon, Sony
Note: Length/weight given for Nikon mount.
Price (Street): $449

For more information, contact Tamron USA, Inc. at: www.tamron-usa.com.